Bifenthrin (BF) is a pyrethroid insecticide used in urban and agricultural applications. Previous studies in early life stages of fish have indicated anti-estrogenic activity; however, estrogenic activity has been observed in adults. To test the hypothesis that BF impairs sex differentiation, larval Japanese Medaka were exposed to BF during a critical developmental window for phenotypic sexual differentiation. Fish were exposed to environmentally relevant concentrations of BF (0.15 μg/L and 1.5 μg/L), a single concentration (0.3 mg/L) of an estrogen receptor (ER) antagonist (ICI 182,780), and an ER agonist (0.2 ug/L) (17β-estradiol). Fish were exposed at 8 days post hatch (dph) larvae for 30 days. Phenotypic sex, secondary sexual characteristics (SSC) and genotypic sex were investigated at sexual maturity (8 weeks). A trend towards masculinization (p = 0.06) based on the presence of papillary processes in anal fin rays of Japanese Medaka was observed in fish exposed to the lowest concentration of BF. However, genotypic gender ratios were not altered. These results show sex differentiation was not significantly altered by larval exposure to BF in Japanese medaka.
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http://dx.doi.org/10.1016/j.envres.2019.108564 | DOI Listing |
Front Immunol
January 2025
Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Japan.
The cellular and molecular mechanisms underlying lymphocyte development are diverse among teleost species. Although recent scRNA-seq analyses of zebrafish hematopoietic cells have advanced our understanding of teleost hematopoiesis, comparative studies using another genetic model, medaka, which is evolutionarily distant among teleosts, is useful for understanding commonality and species-specificity in teleosts. In order to gain insight into how different molecular and cellular mechanisms of lymphocyte development in medaka and zebrafish, we established a () mutant medaka, which exhibited defects in V(D)J rearrangement of lymphocyte antigen receptor genes, accordingly lacking mature B and T cells.
View Article and Find Full Text PDFEnviron Health (Wash)
January 2025
Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543, United States.
In May 2021, the M/V ship fire disaster led to the largest maritime spill of resin pellets (nurdles) and burnt plastic (pyroplastic). Field samples collected from beaches in Sri Lanka nearest to the ship comprised nurdles and pieces of pyroplastic. Three years later, the toxicity of the spilled material remains unresolved.
View Article and Find Full Text PDFJ Hazard Mater
January 2025
Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen 361102, China; State Key Laboratory of Mariculture Breeding, Xiamen University, Xiamen 361102, China. Electronic address:
Tinidazole (TNZ), a common nitroimidazole antibiotic, is pervasive in aquatic ecosystems, posing potential threats to marine organisms. The environmental fate of TNZ, particularly under solar irradiation, and the associated secondary risks are not well characterized. Herein, the photochemical reactivity of TNZ and four other typical nitroimidazoles (i.
View Article and Find Full Text PDFSci Total Environ
January 2025
Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8563, Chiba, Japan; Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa 277-8564, Chiba, Japan.
In recent decades, microplastics (MPs) have emerged as one of the biggest environmental challenges in aquatic environments. Ingestion and toxicity of MPs in seawater (SW) and freshwater (FW) fish have been studied extensively both in field and laboratory settings. However, the basic mechanism of how fish deal with MPs in SW and FW remains unclear, although physiological conditions of fish differ significantly in the two environments.
View Article and Find Full Text PDFR Soc Open Sci
January 2025
Laboratory of Animal Sociology, Department of Biology, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan.
In animals where males engage in multiple matings, sperm depletion can substantially reduce the reproductive success of both sexes. However, little is known about how successive matings affect sperm depletion, fertilization rates and mating behaviour. Here, we investigated this phenomenon under laboratory conditions.
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